Treatment of Inflammatory Lesions of Rosacea with Ivermectin

ABSTRACT

Methods for safe and effective treatment of inflammatory lesions of rosacea in a subject are described. The methods involve once daily topically applying to an affected skin area a topical composition containing ivermectin and a pharmaceutically acceptable carrier. It has been demonstrated that once daily topical treatment with ivermectin is significantly superior than twice-daily topical treatment with metronidazole in reducing inflammatory lesion counts.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is of U.S. patent application Ser. No. 16/549,405,filed Aug. 23, 2019, which is a continuation of U.S. patent applicationSer. No. 15/902,109, filed Feb. 22, 2018, which is a continuation ofU.S. patent application Ser. No. 14/903,949, filed Jan. 8, 2016, whichis a Section 371 of International Application No. PCT/US14/45717, filedJul. 8, 2014, which was published in the English language on Jan. 15,2015, under International Publication No. WO 2015/006305 A2, whichclaims priority from U.S. patent application Ser. No. 14/209,927, filedMar. 13, 2014, which is entitled to priority pursuant to 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 61/843,540, filed Jul.8, 2013, U.S. Provisional Patent Application No. 61/919,208 filed Dec.20, 2013, and U.S. Provisional Patent Application No. 61/927,717, filedJan. 15, 2014, the disclosure of each of which is hereby incorporated byreference herein in its entirety.

BACKGROUND OF THE INVENTION

Rosacea is a highly prevalent, chronic inflammatory skin conditionestimated to affect 16 million Americans.¹⁻² Rosacea is a common,chronic and progressive inflammatory disease with skin featurescharacterized by blushing and flushing, facial erythema, papules,pustules, telangiectasia and sometimes ocular lesions known as ocularrosacea. In severe cases, particularly in men, rhinophyma, or a bulbousenlargement of the nose, may occur. Rosacea develops over the course ofseveral years with periods of exacerbation triggered by various stimulisuch as temperature changes, alcohol, spicy foods, sun exposure andemotional factors.

The prevalence of rosacea in the European population ranges between 0.09and 22%, with a peak age of onset between 25 and 70 and is much morecommon in people with a light complexion. It more particularly affectswomen although the condition is generally more severe in men. Theprevalence of family histories of rosacea has been reported.

Four subtypes of rosacea have been defined according to the degree ofprimary features, such as vasomotor flushing, persistent erythema,papules and pustules, telangiectasias (Wilkin J et al., JAAD, 2002, 46:584-587). Erythematotelangiectatic rosacea (ETR) is mainly characterizedby vasomotor flushing and persistent central facial erythema.Telangiectasias are commonly observed but are not essential for thediagnosis of this subtype. Central facial edema, burning or stingingsensations and rough, flaky skin are also symptoms that have sometimesbeen reported. A history of flushing as the only symptom is commonlyfound in people with erythematotelangiectatic rosacea.

Papulopustular rosacea (PPR) is characterized by persistent centralfacial erythema and transient crops of papules and/or pustules in thecenter of the face. However, the papules and pustules can also occur inperiorificial regions, i.e., around the mouth, nose and eyes. Thepapulopustular subtype resembles acne vulgaris, but comedones areabsent. Rosacea and acne may coexist in a same patient, in which casecomedones may also be present alongside the papules and pustulessuggestive of rosacea. People with papulopustular rosacea sometimescomplain of a burning or stinging sensation. This subtype is oftenobserved before or at the same time as ETR (including the presence oftelangiectasias). The telangiectasias may be obscured by the persistenterythema and the papules and pustules, but they tend to become morevisible after successful treatments that cover up these features.Papulopustular rosacea (PPR) is a subtype of the inflammatory lesionsthat is associated with great psychological distress.³ Facial blemisheshave been found to significantly impair health-related quality of life,along with a fear of negative evaluation by others.⁴ Moreover, PPR ischaracterized by the presence of inflammatory infiltrates that accompanyflares, along with a heightened immune response involving neutrophilicinfiltration and increased gene expression of IL-8 (Steinhoff et al. JInvestig Dermatol Symp Proc 2011; 15:2-11)

Phymatous rosacea is characterized by a thickening of the skin,irregular surface nodularities and swelling. The nose is most commonlyaffected but phymatous rosacea can also involve other areas such as thechin, the forehead, the cheeks and the ears. Patients with this subtypesometimes exhibit prominent, enlarged follicles in the affected areas aswell as telangiectasias. This subtype often occurs before or at the sametime as ETR or PPR (including the presence of persistent erythema,telangiectasias, papules and pustules). In the case of rhinophyma, theseadditional stigmata may be particularly pronounced in the nasal region.

Ocular rosacea (or ophthalmic rosacea) exhibits symptoms restricted tothe ocular area with blepharitis, conjunctivitis and keratitis. Thediagnosis of ocular rosacea should be considered when a patient presentswith one or more of the following ocular signs and symptoms: watery orbloodshot eyes (interpalpebral conjunctival hyperemia), foreign bodysensation, burning or stinging, dry or itchy eyes, sensitivity to light,blurred vision, conjunctival telangiectasias or eyelid margintelangiectasias or erythema of the eyelid and periocular area.

The pathogenesis of rosacea is not yet completely understood. Itsetiology is multifactorial. In addition to exogenous factors (includingUV light, heat and alcohol), it may be secondary to parasiticinvolvement (particularly Demodex folliculorum mites).⁵⁻⁶ Such factorsactivate neurovascular and/or immune responses, and consequentlyinflammatory cascades. Intermittent flares may contribute to thechronicity of rosacea as they are associated with prolongedvasodilation, perivascular inflammation, edema and exposure to cytokinesand cellular infiltrates. Some studies of PPR observed higher mitedensities compared to controls (Forton et al., Br J Dermatol 1993;128(6):650-9; Karincaoglu et al., J Dermatol 2004; 31(8):618-26). Skinaffected by rosacea is highly sensitive and prone to irritation.⁷

Management of rosacea is difficult and currently the most used therapiescomprise oral antibiotics (tetracycline or its derivatives,metronidazole and macrolides) and oral retinoids. There are only a fewcurrent treatment options for inflammatory lesions of rosacea, and notmany alternatives exist with high efficacy and once-daily dosing. Arecent Cochrane review noted that it is unclear which is most effective,while some evidence supports the efficacy of topical metronidazole,azelaic acid and subantimicrobial-dose doxycycline in the treatment ofmoderate to severe rosacea.⁸ In a national survey of current rosaceamedication users, 46% of patients had previously changed medications,usually due to a lack of improvement.⁹ Slow and incomplete treatment,and short period of relapse-free time have been noticed with someconventional treatments.

Ivermectin is an anti-parasitic drug derivative from the macrocycliclactones family approved for human use for treatment andchemoprophylaxis of onchocerciasis and strongyloidiasis since 1996 inthe USA and since 1988 in France. In addition, it has been in approvedin France for the treatment of human scabies. Oral ivermectin in humanand animal demodicidosis was effective in reducing Demodex folliculorumand improving demodicidosis. Moreover, when administered orally,ivermectin combined with a subsequent weekly application of topicalpermethrin showed treatment efficacy in a patient presenting chronicrosacea-like demodicidosis (14).

U.S. Pat. No. 5,952,372 discloses a method of treating rosacea in humansinvolving orally or topically administering ivermectin. However,according to U.S. Pat. No. 5,952,372, because of the skin barriereffect, topical treatment with ivermectin would be anticipated torequire once- or twice-daily applications for as long as four weeks toachieve sufficient follicle penetration and effective miticidalactivity. It further describes that after ivermectin carries out itsmiticidal activity on skin Demodex folliculorum organisms, inflammatoryresponses to them begin to diminish but remnants of the dead mites stillelicit some flushing and lesion formation until the cleanup processes ofthe body remove them, a process that requires six to eight weeks. Itsuggests to employ conventional anti-rosacea medications, such as oraltetracycline and topical metronidazole, to suppress early flareups andto give early clinical response during the initial phase of ivermectinadministration. U.S. Pat. No. 5,952,372 contains no specific disclosureon topical treatment of PPR.

U.S. Pat. Nos. 6,133,310 and 8,415,311 also disclose a method oftreating acne rosacea by topical application of ivermectin. However,they contain no specific disclosure on treating inflammatory lesions ofrosacea or PPR.

Accordingly, there is a need for an once-daily topical treatment ofinflammatory lesions of rosacea with an earlier onset of significanteffectiveness and a prolonged time to relapse than the currentlyavailable treatments, in order to provide safe, more rapid and longerlasting relief, and better patient compliance to those in need of suchtreatment. Such need is met by the present invention.

BRIEF SUMMARY OF THE INVENTION

It is now demonstrated that topical administration of 0.5 to 1.5% byweight of ivermectin provided more rapid relief of inflammatory lesionsof rosacea as well as longer period of time that is free of relapse ascompared to the currently available treatments, such as the topicaltreatment with 0.75% by weight of metronidazole.

In one general aspect, embodiments of the present invention relate to amethod of treating inflammatory lesions of rosacea in a subject in needthereof, comprising topically administering, once daily, to a skin areaaffected by the inflammatory lesions of rosacea a pharmaceuticalcomposition comprising 0.5% to 1.5% by weight ivermectin and apharmaceutically acceptable carrier, wherein as early as 2 weeks afterthe initial administration of the pharmaceutical composition, asignificant reduction in inflammatory lesion count is observed.

In another general aspect, the present invention relates to a method oftreating inflammatory lesions of rosacea in a subject in need thereof,comprising topically administering, once daily, to a skin area affectedby the inflammatory lesions a pharmaceutical composition comprising 1%by weight ivermectin and a pharmaceutically acceptable carrier, whereinas early as 2 weeks after the initial administration of thepharmaceutical composition to the subject, a significant reduction ininflammatory lesion count is observed and a steady state of plasmaconcentration of ivermectin is reached in the subject, wherein thesteady state has a mean C_(max) of ivermectin of 2.10±1.04 ng/mL with arange of 0.69-4.02 ng/mL, and a mean AUC-24 hr of 36.14±15.56 ng·hr/mLwith a range of 13.69-75.16 ng·hr/mL.

In a preferred embodiment of the present invention, the subject hasmoderate to severe papulopustular rosacea before the treatment.

In another preferred embodiment of the present invention, the subjecthas at least 10, preferably at least 12 and more preferably at least 15,inflammatory lesions of rosacea, before the treatment.

According to embodiments of the present invention, once daily topicaltreatment with ivermectin is significantly superior than twice-dailytopical treatment with metronidazole in treating inflammatory lesions ofrosacea.

Other aspects, features and advantages of the invention will be apparentfrom the following disclosure, including the detailed description of theinvention and its preferred embodiments and the appended claims.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The foregoing summary, as well as the following detailed description ofthe invention, will be better understood when read in conjunction withthe appended drawings. For the purpose of illustrating the invention,there are shown in the drawings embodiments which are presentlypreferred. It should be understood, however, that the invention is notlimited to the precise embodiments shown in the drawings.

FIG. 1 shows the median percentage change from baseline in lesion counts(ITT-LOCF population) in a dose range study, after various topicaltreatments;

FIG. 2 illustrates subjects' response to the statement “the productimproves my rosacea” after various topical treatments (ITT Observed);

FIG. 3 shows subject disposition in 2 clinical studies on the safety andefficacy of ivermectin topical treatment;

FIGS. 4A, 4B, and 4C illustrate proportions of subjects achieving IGAsuccess (“clear” or “almost clear”): (FIG. 4A) at week 12 in studies 1and 2; (FIG. 4B) at weeks 2, 4, 8 and 12 in study 1; and (FIG. 4C)) atweeks 2, 4, 8 and 12 in study 2, wherein SOOLANTRA is a 1% ivermectincream;

FIGS. 5A, 5B, 5C, and 5D show the change from baseline in inflammatorylesion counts (ITT-LOCF): (FIG. 5A) mean absolute change (standarderror) in study 1; (FIG. 5B) mean absolute change (standard error) instudy 2; (FIG. 5C) median percent change in study 1; and (FIG. 5D)median percent change in study 2, wherein SOOLANTRA is a 1% ivermectincream;

FIGS. 6A and 6B show subjects' rating of rosacea improvement in (FIG.6A) Study 1 and (FIG. 6B) Study 2 at week 12;

FIG. 7 are photographs of a patient at Baseline and Week 12 (standardlight);

FIG. 8 shows subject disposition in a clinical study comparing thetopical treatments with ivermectin and metronidazole;

FIG. 9 illustrates the mean percent change from baseline in inflammatorylesion counts (ITT-LOCF) after the topical treatments with ivermectinand metronidazole, * p<0.05, **p<0.001;

FIG. 10 shows the success rate based on IGA of “clear” or “almost clear”after the topical treatments with ivermectin and metronidazole, *p<0.05, ** p<0.001;

FIG. 11 shows subjects' rating of rosacea improvement after the topicaltreatments with ivermectin and metronidazole;

FIG. 12. shows time to first relapse defined as first re-occurrence ofIGA≥2 after the successful treatments with ivermectin (CD5024) andmetronidazole; and

FIG. 13. illustrates overall mean ivermectin plasma concentrations (SD,with N=15).

DETAILED DESCRIPTION OF THE INVENTION

Various publications, articles and patents are cited or described in thebackground and throughout the specification; each of these references isherein incorporated by reference in its entirety. Discussion ofdocuments, acts, materials, devices, articles, or the like which havebeen included in the present specification is for the purpose ofproviding context for the present invention. Such discussion is not anadmission that any or all of these matters form part of the prior artwith respect to any inventions disclosed or claimed.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood to one of ordinary skill inthe art to which this invention pertains. Otherwise, certain terms usedherein have the meanings as set forth in the specification. All patents,published patent applications and publications cited herein areincorporated by reference as if set forth fully herein. It must be notedthat as used herein and in the appended claims, the singular forms “a,”“an,” and “the” include plural references unless the context clearlydictates otherwise.

Ivermectin is a member of the avermectin class, which has been shown inimmunopharmacological studies to exert anti-inflammatory effects byinhibiting lipopolysaccharide-induced production of inflammatorycytokines, such as tumor necrosis factor alpha and interleukin (IL)-1b,while upregulating the anti-inflammatory cytokine IL-10¹⁰. It is asemi-synthetic derivative isolated from the fermentation of Streptomycesavermitilis, that belongs to the avermectin family of macrocycliclactones. Ivermectin is a mixture containing5-O-demethyl-22,23-dihydroavermectin A1a plus5-O-demethyl-25-de(1-methylpropyl)-25-(1-methylethyl)-22,23-dihydroavermectinA1a, generally referred to as 22,23-dihydroavermectin B1a and B1b orH2B1a and H2B1b, respectively. The respective empirical formulas ofH2B1a and H2B1b are C₄₈H₇₄O₁₄ and C₄₇H₇₂O₁₄ with molecular weights of875.10 and 861.07 respectively.

Ivermectin is a macrocyclic lactone derivative, its therapeutic effectis thought to be prominently due to its anti-inflammatory properties,similar to that of other macrolides.¹¹⁻¹² Avermectin has been reportedto exert anti-inflammatory effects by inhibitinglipopolysaccharide-induced production of inflammatory cytokines. Inaddition to its anti-inflammatory mode of action, ivermectin possessesantiparasitic properties. Its predecessor, avermectin, is anantiparasitic agent of agricultural importance first isolated in 1974.¹³Several studies support ivermectin's role in the effective oraltreatment of cutaneous demodicidosis (in combination with topicalpermethrin cream) and scabies, as well as topical treatment of headlice.¹⁴⁻¹⁶ Ivermectin causes death of parasites, primarily throughbinding selectively and with high affinity to glutamate-gated chloridechannels, which occur in invertebrate nerve and muscle cells. This leadsto the interruption of nerve impulses, causing paralysis and death ofparasitic organisms. Ivermectin is known to act on Demodex mites inlocalized and generalized demodicidosis in animals and in humans.

In the present invention, studies were conducted to evaluate theefficacy and safety of ivermectin in treating inflammatory lesions ofrosacea, such as papulopustular rosacea (PPR).

It was discovered that, as early as 2 weeks after the initial topicaladministration of a pharmaceutical composition comprising 0.5 to 1.5%(w/w) ivermectin to the subject, a significant reduction in inflammatorylesion count was observed.

As used herein, a “significant reduction” refers to a reduction that isstatistically significant, not due to chance alone, which has a p-valueof 0.05 or less. A “significant reduction” can have a p-value of lessthan 0.05, 0.04, 0.03, 0.01, 0.005, 0.001, etc. As used herein,“inflammatory lesion count” refers to the number of inflammatory lesionsassociated with rosacea or PPR. Inflammatory lesions can be papulesand/or pustules. A papule is a small, solid elevation less than onecentimeter in diameter, and a pustule is a small, circumscribedelevation of the skin, which contains yellow-white exudates.

The lesions can be, e.g., papules and/or pustules of any sizes (small orlarge). For example, at two weeks after the initial treatment, about 30%(p<0.001) and 27.3% (p<0.01) median reduction of the inflammatory lesioncounts were observed from patients treated with ivermectin in twoseparate clinical studies using methods of the present invention. Thesereductions are statistically significant because they had p values lessthan 0.01 or even less than 0.001.

This early onset of significant effectiveness is unexpected andsurprising in comparison to the conventional treatments. For example,significant treatment differences were only observed from week 4 or week8 forward in two phase III studies for the topical treatment of moderatePPR using twice-daily 15% azelaic acid (Thiboutot et al., 2003, J AmAcad Dermatol, 48 (6): 836-845), while no statistically significantdifference with respect to the median inflammatory lesion counts or themedian percentage change in inflammatory lesion counts was observed atany evaluation time during the study (P≥0.29) of topical treatment ofmoderate to severe PPR using once-daily 0.75% or 1.0% metronidazole(Dahl et al., 2001, J. Am Acad Dermatol, 45 (5): 723-730).

This early onset of significant effectiveness is also unexpected andsurprising in view of the prior teaching that topical treatment withivermectin would be anticipated to require once- or twice-dailyapplications for as long as four weeks to achieve sufficient folliclepenetration and effective miticidal activity; and that after ivermectincarries out its miticidal activity on skin Demodex folliculorumorganisms, remnants of the dead mites still elicit some flushing andlesion formation until the cleanup processes of the body remove them, aprocess that requires six to eight weeks; and that conventionalanti-rosacea medications, such as oral tetracycline and topicalmetronidazole, are suggested to be employed to suppress early flareupsand to give early clinical response during the initial phase ofivermectin administration (see, e.g., U.S. Pat. No. 5,952,372).

In addition, it was discovered in the present invention that afterrepeated topical administration of a pharmaceutical compositioncomprising 0.5 to 1.5% (w/w) ivermectin and a pharmaceuticallyacceptable carrier, plasma concentrations of ivermectin increasedprogressively until reaching a plateau or steady state. It was alsoobserved that the repeated topical administration results in a muchlonger terminal half-life of ivermectin in the subject than that fororally administered ivermectin, indicating that the rate limiting stepin the decrease of plasma ivermectin concentration is the slow andconstant release of ivermectin from the administration site on skin intothe blood, rather than the rate of eliminating ivermectin from theblood, i.e., a “flip flop” phenomenon (Toutain et al, 2004, J. Vet.Pharmacol. Therap. 27: 427-439). Surprisingly, despite thisrate-limiting factor of slow and constant release of ivermectin from theskin into the blood, no further systemic accumulation of ivermectin wasobserved after prolonged topical treatment with 0.5 to 1.5% (w/w)ivermectin. Thus, a topical treatment according to an embodiment of thepresent invention is safe and can be conducted for as long as it isneeded without causing any safety concerns.

Side-by-side clinical studies in the present invention also showed thatmethods according to embodiments of the present invention result in morereduction in inflammatory lesion counts as well as longer time for therelapse of inflammatory lesions to occur than the conventional topicaltreatment, such as that with metronidazole. In addition, methodsaccording to embodiments of the present invention also result in lessfrequent adverse skin reactions than the conventional topicaltreatments.

While not wishing to be bound by the theory, it is believed that themechanism of action of ivermectin in treating inflammatory lesions ofrosacea may be linked to anti-inflammatory effects of ivermectin as wellas the death of Demodex mites that have been reported to be a factor ininflammation of the skin. Because ivermectin has both anti-inflammatoryand anti-parasitic activities, treatment of inflammatory lesions withivermectin represents an innovative therapy addressing these relevantpathogenic factors in rosacea, thus a novel addition to the currenttreatment armamentarium.

According to an embodiment of the present invention, a method oftreating inflammatory lesions of rosacea in a subject in need thereof,comprises topically administering, once daily, to a skin area affectedby the inflammatory lesions of rosacea a pharmaceutical compositioncomprising 0.5% to 1.5% by weight ivermectin and a pharmaceuticallyacceptable carrier, wherein as early as 2 weeks after the initialadministration of the pharmaceutical composition, a significantreduction in inflammatory lesion count is observed.

As used herein, “pharmaceutically acceptable carrier” refers to apharmaceutically acceptable vehicle or diluent comprising excipients andauxiliaries that facilitate processing of the active compounds intopreparations which can be used pharmaceutically.

The pharmaceutical compositions according to the invention are suitedfor treating the skin. They can be in liquid, pasty or solid form, andmore particularly in the form of ointments, creams, milks, pomades,powders, impregnated pads, syndets, towelettes, solutions, gels, sprays,foams, suspensions, lotions, sticks, shampoos or washing bases. They canalso be in the form of suspensions of microspheres or nanospheres or oflipid or polymeric vesicles or of polymeric patches and of hydrogels forcontrolled release. These compositions for topical application can be inanhydrous form, in aqueous form, or in the form of an emulsion.

In one embodiment of the present invention, the pharmaceuticalcomposition being formulated as an emulsion, the topical pharmaceuticalemulsion comprises ivermectin, and one or more other ingredientsselected from the group consisting of an oily phase comprisingdimethicone, cyclomethicone, isopropyl palmitate and/or isopropylmyristate, the oily phase further comprising fatty substances selectedfrom the group consisting of cetyl alcohol, cetostearyl alcohol, stearylalcohol, palmitostearic acid, stearic acid and self-emulsifiable wax; atleast one surfactant-emulsifier selected from the group consisting ofglyceryl/PEG100 stearate, sorbitan monostearate, sorbitan palmitate,Steareth-20, Steareth-2, Steareth-21 and Ceteareth-20; a mixture ofsolvents and/or propenetrating agents selected from the group consistingof propylene glycol, oleyl alcohol, phenoxyethanol and glyceryltriacetate; one or more gelling agents selected from the groupconsisting of carbomers, cellulose gelling agents, xanthan gums,aluminum magnesium silicates but excluding aluminum magnesiumsilicate/titanium dioxide/silica, guar gums, polyacrylamides andmodified starches; and water.

In a preferred embodiment of the present invention, the pharmaceuticalcomposition comprises about 1% (w/w) ivermectin, and a pharmaceuticallyacceptable carrier.

In another preferred embodiment of the present invention, thepharmaceutical composition comprises about 1% (w/w) ivermectin, and oneor more inactive ingredients selected from the group consisting ofcarbomer, such as carbomer copolymer type B; cetyl alcohol; citric acidmonohydrate; dimethicone 20 Cst; edetate disodium; glycerin; isopropylpalmitate; methyl paraben; oleyl alcohol; phenoxyethanol; polyoxyl 20cetostearyl ether; propylene glycol; propyl paraben; purified water;sodium hydroxide; sorbitan monostearate and stearyl alcohol.

As used herein, the term “subject” means any animal, preferably amammal, most preferably a human, to whom will be or has beenadministered compounds or topical formulations according to embodimentsof the invention. Preferably, a subject is in need of, or has been theobject of observation or experiment of, treatment or prevention ofinflammatory lesions of rosacea or papulopustular rosacea.

As known to those skilled in the art, an “intent-to-treat population” or“ITT population” refers to all subjects who are randomized in a clinicalstudy and to whom the study drug is administered. “ITT-LOCF” refers tothe ITT population using the Last Observation Carried Forward (LOCF)method, a standard method of handling missing data that imputes or fillsin values based on existing data. “ITT-MI” refers to the ITT populationusing the multiple imputations (MI) method based on all the dataavailable in the model, another method for processing data known tothose skilled in the art. A “per protocol population” or “PP population”refers to subjects of the ITT population in a clinical study who have nomajor deviations from the protocol of study.

As used herein, the term “inflammatory lesions of rosacea” include anytype of skin lesions associated with the inflammatory phase of rosacea.Examples of “inflammatory lesions of rosacea” include various sizes ofpapules and pustules associated with rosacea. In a preferred embodimentof the present invention, the inflammatory lesions of rosacea compriseinflammatory lesions of papulopustular rosacea (PPR), more preferablyinflammatory lesions of moderate to severe PPR.

In one embodiment, “treatment” or “treating” refers to an amelioration,prophylaxis, or reversal of a disease or disorder, or of at least onediscernible symptom thereof. In another embodiment, “treatment” or“treating” refers to an amelioration, prophylaxis, or reversal of atleast one measurable physical parameter related to the disease ordisorder being treated, not necessarily discernible in or by the mammal.In yet another embodiment, “treatment” or “treating” refers toinhibiting or slowing the progression of a disease or disorder, eitherphysically, e.g., stabilization of a discernible symptom,physiologically, e.g., stabilization of a physical parameter, or both.In yet another embodiment, “treatment” or “treating” refers to delayingthe onset of a disease or disorder.

Success of treating inflammatory lesions of rosacea or PPR can bemeasured using methods known in the art, such as by the reduction ofinflammatory lesion count from the baseline before treatment, by animprovement from the baseline in an investigator's global assessment(IGA) score, or by both the reduction of inflammatory lesion count andthe IGA score.

The IGA score is determined by a trained medical professional evaluatingthe skin condition of a patient utilizing an investigative globalassessment of the skin condition. Typically, such global assessmentsassign a value to the degree of rosacea exhibited by the skin. Inaddition to the assessment made by the medical professional, thepatient's input and observations of their skin condition and responsesto various inquiries (e.g., stinging or burning sensations) also play arole in determining the IGA score that is assigned. For example, the IGAscore for rosacea (Table 1) can range, for example, from 0 (clear) to 1(almost clear) to 2 (mild) to 3 (moderate) to 4 (Severe), includingvalues between these numeric gradings, such as 1.5, 2.6, 3.4 etc. (e.g.,intervals of 0.1).

TABLE 1 Investigator's Global Assessment of Rosacea Severity Grade ScoreClinical Description Clear 0 No inflammatory lesions present, noerythema Almost 1 Very few small papules/pustules, very mild Clearerythema present Mild 2 Few small papules/pustules, mild erythemaModerate 3 Several small or large papules/pustules, moderate erythemaSevere 4 Numerous small and/or large papules/pustules, severe erythema

In view of the present disclosure, a skin area that is affected byinflammatory lesions of rosacea or papulopustular rosacea can beidentified using any diagnostic signs or means known in the art, and canbe treated by methods according to embodiments of the present invention.Patients can have papulopustular rosacea at different stages, from mildto severe.

In a preferred embodiment, the patient has moderate to severepapulopustular rosacea. As used herein, a patient having “moderate tosevere papulopustular rosacea” has at least moderate facial erythema andat least 10 papulopustular lesions before treatment. For example, thepatient can have an IGA of rosacea of 3 or 4, and at least 10, 12, 15,20, 25 or more papulopustular lesions before treatment.

According to embodiments of the present invention, the inflammatorylesions of rosacea or papulopustular rosacea is treated by topicallyapplying to an affected skin area a pharmaceutical compositioncomprising ivermectin and a pharmaceutically acceptable carrier, and thetreatment results in a reduction in the inflammatory lesion count ofrosacea from the baseline number of lesions (before treatment) by atleast 1 to 100 lesions or more, such as at least 1, 2, 3, 4, 5, 6, 7, 8,9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26,27, 28, 29, 30, 35, 40, 50, 60, 70, 80, 90 or 100 lesions or more.According to embodiments of the present invention, at least about 10%,20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or 100% reduction in inflammatorylesion count is observed after the treatment. Depending on the number ofinflammatory lesions, and other factors, such as the conditions of thepatient, the treatment can last as long as it is needed, such as 4 to 12weeks.

According to other embodiments of the present invention, the treatmentreduces the IGA score in the treated subject. As used herein, the“success rate” in a clinical study refers to the percentage of subjectsin the study having an IGA of 0 (“clear”) or 1 (“almost clear”) afterthe treatment.

According to embodiments of the present invention, after the initialsuccessful treatment with ivermectin, i.e., to an IGA of 0 or 1, ittakes a longer time to relapse, i.e., to an IGA of 2 or above, ascompared to the conventional treatments, such as topical treatment with0.75% by weight metronidazole. For example, treatment with ivermectin(1%) once daily (QD) resulted in a statistically significant extendedremission (e.g., delayed time to first relapse, and increase in thenumber of treatment free days) of rosacea when compared to metronidazole0.75% BID in subjects who were successfully treated (IGA 0 or 1) for 16weeks. There was also a numerical trend in favor of ivermectin 1% QD forthe relapse rates.

As used herein, “time to first relapse” is defined as the time elapsedbetween initial successful treatment to an IGA of rosacea of 0 or 1 tothe first reoccurrence of the IGA to 2 or more in a subject. Accordingto embodiments of the present invention, the median time to firstrelapse is about 110, 115, 120, 125, 130, 135, 140, 145 or 150 days ormore in subjects treated with ivermectin, with a p value of 0.05 orless.

Another aspect of the present invention relates to a method of treatingpapulopustular rosacea in a subject in need thereof, comprisingtopically administering, once daily, to a skin area affected by thepapulopustular rosacea a pharmaceutical composition comprising 1% byweight ivermectin and a pharmaceutically acceptable carrier, wherein asearly as 2 weeks after the initial administration of the pharmaceuticalcomposition to the subject, a significant reduction in inflammatorylesion count is observed.

Preferably the subject has moderate to severe PPR. More preferably, thesubject has at least 15 inflammatory lesions of PPR before thetreatment.

In another preferred embodiment, at two weeks after the initialtreatment, about 27% or more median reduction of the inflammatory lesioncounts is observed from subjects treated with ivermectin, with a p valueof 0.01 or less.

In an embodiment of the present invention, as early as 2 weeks after theinitial administration of the pharmaceutical composition to the subject,more reduction in the inflammatory lesion count in the subject isobserved as compared with a vehicle control. In other embodiments of thepresent invention, the method results in more reduction of theinflammatory lesion count in the subject in comparison to that achievedby topically administering to the subject a second pharmaceuticalcomposition comprising 0.75% by weight metronidazole.

According to an embodiment of the present invention, a steady state ofplasma concentrations of ivermectin is reached in the subject afterrepeated administration. For example, after about two weeks of oncedaily topical administration of a pharmaceutical composition containingabout 1% (w/w) ivermectin, a steady state of plasma concentration ofivermectin is reached. At this steady state, a mean C_(max), i.e., thehighest mean (standard deviation) plasma concentration of ivermectin,peaked within 10±8 hours post-dose, is 2.10±1.04 ng/mL (range: 0.69-4.02ng/mL), and a highest mean (±standard deviation) AUC_(0-24hr) is36.14±15.56 ng·hr/mL (range: 13.69-75.16 ng·hr/mL). These levelsobtained under steady-state conditions are lower than those observedfollowing oral administration of ivermectin.

According to an embodiment of the present invention, at the steadystate, the C_(max) of ivermectin ranges from about 0.5 to 10 ng/mL andthe AUC-24 hr ranges from about 10 to 100 ng·hr/mL in the subject.

According to another embodiment of the present invention, the topicaladministration of the pharmaceutical composition to the subject resultsin a mean terminal half-life of ivermectin in the subject that is muchlonger than that from orally administered ivermectin. In an embodimentof the present invention, the topical administration of thepharmaceutical composition to the subject results in a mean terminalhalf-life of ivermectin in the subject of about 145 hours in thesubject.

In an embodiment of the present invention, a method of treatinginflammatory lesions of rosacea in a subject in need thereof, comprisestopically administering, once daily, to a skin area affected by theinflammatory lesions a pharmaceutical composition comprising 1% byweight ivermectin and a pharmaceutically acceptable carrier, wherein asearly as 2 weeks after the initial administration of the pharmaceuticalcomposition to the subject, a significant reduction in inflammatorylesion count is observed and a steady state of plasma concentration ofivermectin is reached in the subject, and the steady state has a meanC_(max) of ivermectin of 2.10±1.04 ng/mL with a range of 0.69-4.02ng/mL, and a mean AUC-24 hr of 36.14±15.56 ng·hr/mL with a range of13.69-75.16 ng·hr/mL.

This invention will be better understood by reference to thenon-limiting examples that follow, but those skilled in the art willreadily appreciate that the examples are only illustrative of theinvention and the claims which follow thereafter.

Unless otherwise indicated, all percentages of the ingredients in thepresent application are percentages by weight (w/w).

Example 1: Topical Ivermectin Compositions

Examples of pharmaceutical compositions that can be used in the presentinvention are described in U.S. Pat. Nos. 8,415,311 and 8,470,788, whichare incorporated herein by reference. Compositions useful in the presentinvention include, but are not limited to, the following:

Composition 1 % by weight relative to the total weight of theIngredients Composition Ivermectin 1.00 Glycerol 4.0 Aluminum magnesiumsilicate 1.0 Methyl para-hydroxybenzoate 0.2 Disodium EDTA 0.05 Citricacid monohydrate 0.05 Isopropyl palmitate 4.0 Glyceryl/PEG 100 stearate3.0 Self-emulsifiable wax 2.0 Palmitostearic acid 2.5 Steareth-20 3.0Sorbitan stearate 2.0 Dimethicone 20 0.5 Propyl para-hydroxybenzoate 0.1Propylene glycol 4.0 Glyceryl triacetate 1.0 Phenoxyethanol 0.5 10%sodium hydroxide qs pH Water qs 100

Composition 2 % by weight relative to the total weight of theIngredients composition Ivermectin 1.00 Glycerol 4.0 Acrylate C10-30alkyl acrylate 0.15 Crosspolymer Methyl para-hydroxybenzoate 0.2Disodium EDTA 0.05 Citric acid monohydrate 0.05 Isopropyl myristate 4.0Cetyl alcohol 3.0 Stearyl alcohol 2.0 Self-emulsifiable wax 0.8Palmitostearic acid 0.5 Steareth-20 2.0 Sorbitan palmitate 1.0Dimethicone 20 0.5 Propyl para-hydroxybenzoate 0.1 Propylene glycol 4.0Glyceryl triacetate 1.0 Phenoxyethanol 0.5 10% sodium hydroxide qs pHWater qs 100

Composition 3 % by weight relative to the total weight of theIngredients composition Ivermectin 1.00 Glycerol 4.0 Aluminum magnesiumsilicate 1.0 Methyl para-hydroxybenzoate 0.2 Disodium EDTA 0.05 Citricacid monohydrate 0.05 Isopropyl palmitate 4.0 Glyceryl/PEG 100 stearate3.0 Self-emulsifiable wax 2.0 Palmitostearic acid 3.0 Steareth-20 3.0Sorbitan palmitate 2.0 Dimethicone 20 0.5 Propyl para-hydroxybenzoate0.1 Propylene glycol 4.0 Glyceryl triacetate 1.0 Phenoxyethanol 0.5 10%sodium hydroxide qs pH Water qs 100

Composition 4 % by weight relative to the total weight of theIngredients composition Ivermectin 1.00 Glycerol 4.0 Acrylate C10-30alkyl acrylate 0.2 Crosspolymer Methyl para-hydroxybenzoate 0.2 DisodiumEDTA 0.05 Citric acid monohydrate 0.05 Isopropyl palmitate 4.0 Cetylalcohol 3.5 Stearyl alcohol 2.5 Oleyl alcohol 2.0 Ceteareth-20 3.0Sorbitan monostearate 2.0 Dimethicone 200 20 cs 0.5 Propylpara-hydroxybenzoate 0.1 Propylene glycol 2.0 Phenoxyethanol 1.0 10%sodium hydroxide qs pH Water qs 100

Composition 5 % by weight relative to the total weight of theIngredients composition Ivermectin 1.4 Glycerol 4.0 Acrylate C10-30alkyl acrylate 0.2 Crosspolymer Methyl para-hydroxybenzoate 0.2 DisodiumEDTA 0.05 Citric acid monohydrate 0.05 Isopropyl palmitate 4.0 Cetylalcohol 3.5 Stearyl alcohol 2.5 Oleyl alcohol 2.0 Ceteareth-20 3.0Sorbitan monostearate 2.0 Dimethicone 200 20 cs 0.5 Propylpara-hydroxybenzoate 0.1 Propylene glycol 2.0 Phenoxyethanol 1.0 10%sodium hydroxide qs pH Water qs 100

Example 2: Dosage Study on Topical Treatment of PPR with Ivermectin

A phase II, randomized, investigator-blinded, parallel-group, active-and vehicle-controlled study was conducted to determine the optimalconcentration and dose regimen of topical ivermectin cream for thetreatment of inflammatory lesions of rosacea, and evaluate efficacy andsafety.

Eligible subjects were adults with PPR. The majority of the subjects hadat least 15 facial inflammatory lesions and at least mild facialerythema based on IGA of rosacea severity. Table 2 shows the demographicand baseline clinical characteristics (ITT population) of the subjects

TABLE 2 Ivermectin Ivermectin Ivermectin Ivermectin MetronidazoleVehicle 1% BID 1% QD 0.3% 0.1% 0.75% BID QD (N = 48) (N = 52) (N = 47)(N = 51) (N = 48) (N = 50) Gender, n (%) Female 39 (81.3) 33 (63.5) 29(61.7) 31 (60.8) 34 (70.8) 35 (70.0) Male  9 (18.8) 19 (36.5) 18 (38.3)20 (39.2) 14 (29.2) 15 (30.0) Age, year Mean ± SD 50.9 ± 12.3 50.4 ±14.5 53.4 ± 14.5 52.7 ± 13.8 52.2 ± 15.9 52.2 ± 14.4 Phototype, n (%) I 7 (14.6) 4 (7.7)  6 (12.8) 4 (7.8) 3 (6.3)  7 (14.0) II 28 (58.3) 27(51.9) 20 (42.5) 26 (51.0) 29 (60.4) 28 (56.0) III 12 (25.0) 14 (26.9)17 (36.2) 18 (35.3) 14 (29.2) 15 (30.0) IV 1 (2.1)  7 (13.5) 4 (8.5) 3(5.9) 2 (4.1) 0 Inflammatory lesion, n (%) Mean ± SD 37.3 ± 39.0 35.8 ±18.2 35.1 ± 20.5 31.1 ± 15.0 37.4 ± 23.9 35.8 ± 19.9 Min, max 16, 27016, 93 14, 108 15, 79 15, 153 15, 120 IGA, n (%) 1 = Almost 2 (4.2) 0 1(2.1) 1 (2.0) 1 (2.1) 1 (2.0) Clear 2 = Mild 15 (31.3) 20 (38.5) 15(31.9) 18 (35.3) 18 (37.5) 12 (24.0) 3 = Moderate 28 (58.3) 24 (46.2) 21(44.7) 29 (56.9) 21 (43.8) 28 (56.0) 4 = Severe 3 (6.3)  8 (15.4) 10(21.3) 3 (5.9)  8 (16.7)  9 (18.0)

The subjects were randomized to receive one of the following six (6)regimens for 12 weeks: ivermectin 0.1% (w/w) once-daily (QD), ivermectin0.3% (w/w) QD, ivermectin 1% (w/w) QD, ivermectin 1% (w/w) twice-daily(BID), metronidazole gel 0.75% (w/w) BID, or vehicle QD. The 6 groupswere comparable in terms of demographic and baseline diseasecharacteristics (Table 1): majority were female, Caucasian, with a skinphototype II and a mean age of 51.9±14.2 years. On average, the subjectshad 35.4±23.8 inflammatory lesions, and the majority (51.0%) had an IGAof 3 (moderate).

Inflammatory lesion (sum of papules and pustules) counts, rate ofsuccess [% subjects “clear” or “almost clear” based on Investigator'sGlobal Assessment (IGA), a scale from 0 (clear) to 4 (severe)], erythema[from 0 (none) to 3 (severe)], telangiectasia [from 0 (none) to 3(severe)], adverse events, and satisfaction questionnaire (at the end ofthe study) were determined during the study.

FIG. 1 shows the median percentage change from baseline in lesion counts(ITT-LOCF population).

At week 12, both ivermectin 1% (w/w) QD and BID were significantly moreeffective than vehicle QD in the ITT-LOCF analysis based on thepercentage change from baseline in inflammatory lesion counts (median:−78.3% and −78.9% vs. −60.6%; both p<0.05) (FIG. 1); this was alsoconfirmed in the PP analysis. Although ivermectin 1% (w/w) BID wassignificantly more efficacious than vehicle, its magnitude of effect wasnot greater than ivermectin 1% (w/w) QD. A numeric trend favoringivermectin 1% QD compared with metronidazole 0.75% BID was also observedin terms of median % change from baseline in inflammatory lesion counts[−78.3% vs. −69.2% at Week 12 (ITT-LOCF)]; the sample size was not largeenough to detect differences between these groups.

All ivermectin dose regimens led to a significantly greater success ratethan vehicle (70.8%, 65.4%, 63.8% and 62.7% for ivermectin 1% BID, 1%QD, 0.3% QD and 0.1% QD, respectively, vs. 42.0% for vehicle at Week 12;all p<0.05). Furthermore, the success rate for Metronidazole was 62.5%.No difference was observed in the change in erythema or telangiectasiabetween the active and control groups.

All regimens were safe and well-tolerated, with similarly low incidenceof adverse events. There were no serious related AEs. The majority ofrelated AEs were mild, transient and dermatologic in nature, the mostfrequent for the ivermectin groups being skin discomfort (4 subjects),skin burning sensation (4 subjects), and worsening of rosacea (3subjects).

FIG. 2 illustrates subjects' response to the statement “the productimproves my rosacea” (ITT Observed). With increasing dosage ofivermectin, more subjects agreed with the statement “the productimproves my rosacea” (FIG. 2) and were satisfied with the product (datanot shown). The result was superior in ivermectin 1% QD and BID groupscompared to the metronidazole 0.75% BID group. The majority of subjectsin all Ivermectin groups considered that the product was easy to use (atleast 95.5%), pleasant to use (at least 77.3%), and did not irritate theskin (at least 70.2%).

Topical administration of all tested ivermectin dose regimens (1% BID,1% QD, 0.3% QD and 0.1% QD) led to a significantly greater success ratein treating PPR than vehicle; the result was superior in ivermectin 1%QD and BID groups compared to the metronidazole 0.75% BID group; andonce daily topical administration of 1% (w/w) ivermectin was consideredthe optimal dose regimen, because it was safe, well tolerated, andprovided significantly greater efficacy than vehicle for the treatmentof PPR. Once daily topical administration is further preferred becauseit promotes better patient compliance.

Example 3: Efficacy and Safety Study of Ivermectin 1% Cream

To demonstrate the efficacy and safety of once-daily ivermectin 1% (w/w)cream in subjects with PPR, two identically designed randomized,double-blind, controlled studies were conducted (hereafter designatedStudy 1 and Study 2). Both studies were conducted in accordance with theethical principles of the Declaration of Helsinki and Good ClinicalPractices, and in compliance with local regulatory requirements.

Each study had three parts. In the first part of the study, subjectswith PPR were treated with ivermectin 1% cream (IVM 1%) or vehicle oncedaily at bedtime for 12 weeks. In the second part of the study, subjectsinitially treated with IVM 1% once daily at bedtime continued the sametreatment, while subjects treated with the vehicle once daily switchedto topical treatment with azelaic acid 15% gel twice daily, in themorning and evening. The third part of the study consisted of 4 weekssafety follow-up, without treatment.

Eligible subjects were 18 years or older, with moderate or severepapulopustular rosacea as noted by an IGA of 3 (“several small or largepapules/pustules, moderate erythema”) or 4 (“numerous small and/or largepapules/pustules, severe erythema”), and presenting with 15-70 facialinflammatory lesions (papules and pustules). A total of 683 subjectswith moderate to severe PPR were randomized in Study 1 (IVM 1%: 451,vehicle: 232), and 688 subjects in Study 2 (IVM 1%: 459, vehicle: 229)(FIG. 3).

Eligible subjects received either ivermectin cream 1% cream (once dailyevery day at bedtime) or vehicle cream (once daily every day at bedtime)on the entire face for 12 weeks. They were instructed to apply a thinfilm of cream on the entire face (right and left cheeks, forehead, chinand nose), e.g., in a pea-size amount of the cream, avoiding the upperand lower eyelids, lips, eyes and mouth. Subjects were also instructedto avoid rosacea triggers, such as sudden exposure to heat, certainfoods, and excessive sun exposure. Study visits during the first studywere as follows: screening visits, baseline, weeks 2, 4, 8, and 12 afterthe initial administration.

Efficacy assessments at each visit were the IGA of disease severity, andinflammatory lesion counts (papules and pustules) on each of the fivefacial regions (forehead, chin, nose, right cheek, left cheek). Safetyassessments included adverse events (AEs) throughout the study, localtolerance parameters (stinging/burning, dryness, itching) at each studyvisit evaluated on a 4-point scale [from 0 (none) to 3 (severe)], andlaboratory parameters (hematology and biochemistry) measured before andafter treatment. Other assessments included the subject's evaluation oftheir rosacea improvement at the end of the study (week 12) compared totheir condition at baseline, and two quality of life (QoL)questionnaires [a dermatology-specific instrument, the Dermatology LifeQuality Index (DLQI)],¹⁷ and a rosacea-specific instrument, theRosaQoL™¹⁸ completed at baseline and week 12.

The co-primary efficacy endpoints in both studies were the success ratebased on the IGA outcome and absolute change from baseline ininflammatory lesion counts at the end of week 12 of the studies. Thesuccess rate based on IGA score [% of subjects who achieved “clear” or“almost clear” ratings on the IGA scale at week 12 (ITT-LOCF)] wasanalyzed by the Cochran-Mantel-Haenszel (CMH) test stratified byanalysis site, using the general association statistic. The absolutechange in inflammatory lesion counts from baseline to week 12 (ITT-LOCF)was analyzed by analysis of covariance (ANCOVA). Missing data at week 12in the ITT population were imputed by the LOCF approach. Also,sensitivity analyses were conducted to impute missing data in order toassess the robustness of the primary efficacy results. The secondaryefficacy endpoint was percent change in inflammatory lesion counts frombaseline at week 12 (ITT-LOCF). The QoL questionnaires were analyzedusing the Wilcoxon rank sum test, and other variables were descriptivelyanalyzed. High mean scores from the QoL questionnaires indicated a lowquality of life.

In Studies 1 and 2, the vast majority of subjects completed the study(91.4% and 92.6%, respectively). The treatment groups were similar atbaseline in terms of demographics and baseline disease characteristics,with about 31-33 inflammatory lesions on average and the majority havingmoderate rosacea (Table 3). Most subjects were female (68.2% and 66.7%in Studies 1 and 2, respectively) and Caucasian/white (96.2% and 95.3%),with a mean age of 50.4 and 50.2 years, respectively. Additionally,treatment groups were comparable regarding rates/reasons for early studydiscontinuation (FIG. 3).

TABLE 3 Demographic and baseline clinical characteristics (ITTpopulation) Study 1 Study 2 Total Total (n = 683) (n = 688) Age, yearsMean ± SD 50.4 ± 12.09 50.2 ± 12.29 Min, Max 19, 88 18, 89 Gender, n (%)Female 466 (68.2%) 459 (66.7%) Male 217 (31.8%) 229 (33.3%) Race White657 (96.2%) 656 (95.3%) Black or African  9 (1.3%) 10 (1.5%) AmericanAsian  6 (0.9%) 15 (2.2%) Other 11 (1.6%)  7 (1.0%) Inflammatory Mean ±SD 30.9 ± 14.33 32.9 ± 13.70 lesion counts IGA 3 = Moderate 560 (82.0%)403 (83.3%) 4 = Severe 123 (18.0%)  81 (16.7%)

The proportion of subjects achieving IGA success (“clear” or “almostclear”) at week 12 for Studies 1 and 2 were 38.4% and 40.1%,respectively for IVM 1% compared to 11.6% and 18.8% for vehicle (bothp<0.001; FIG. 4A). A significant difference between treatment arms inboth studies was observed based on IGA since week 4 (10.9% and 11.8%versus 5.6% and 5.7%, respectively; both p<0.05), and was sustaineduntil Week 12 (FIGS. 4B and 4C).

For inflammatory lesion counts, the mean difference between IVM 1% andvehicle from baseline to week 12 was −8.13 lesions for Study 1 and −8.22for Study 2 (both p<0.001 versus vehicle), with a 95% CI of [−10.12,−6.13] and [−10.18, −6.25], respectively (FIGS. 5A and 5B). A meanreduction of 9 lesion counts was observed at week 2 in both studies whentreated with IVM 1% (FIGS. 5A and 5B). Median reduction from baseline ininflammatory lesion counts for both studies was 76.0% and 75.0%,respectively, versus 50.0% for both vehicle groups at week 12 (p<0.001),with significant difference observed by week 2 at a median reduction of30% and 27.3% (FIGS. 5C and 5D). This significant reduction ininflammatory lesion counts as early as week 2 was exceptional whencompared with similar data from treatment with metronidazole or azelaicacid.

Table 4 summarizes efficacy outcomes of both studies at the end of thefirst part 12 week studies

IVM 1% Vehicle IVM 1% Vehicle (N = 451) (N = 232) (N = 459) (N = 229)IGA Number (%) of Subjects  173 (38.4)   27 (11.6)  184 (40.1)   43(18.8) Clear or Almost Clear in the IGA at Week 12 Inflammatory LesionsMean inflammatory lesion 31.0 30.5 33.3 32.2 count at baseline Meaninflammatory lesion 10.6 18.5 11.0 18.8 count at Week 12 Mean AbsoluteChange −20.5 (−64.9) −12.0 (−41.6) −22.2 (−65.7) −13.4 (−43.4) (%) inInflammatory Lesion Count from Baseline at Week 12

The incidence of AEs was comparable between Studies 1 and 2 (40.5% and36.5% for IVM 1% versus 39.4% and 36.5% for vehicle, respectively).Fewer subjects in IVM 1% groups tended to report related AEs than invehicle groups (4.2% and 2.6% versus 7.8% and 6.5%, respectively), aswell as for related dermatologic AEs (3.5% and 1.5% versus 6.9% and5.7%) and related AEs leading to discontinuation (1.3% and 0.2%, versus1.7% for both vehicle groups). A similarly low proportion of subjectsreported serious AEs for IVM 1% and vehicle groups (0.7% and 1.5% versus0.4% and 1.7%). There were no related serious AEs. The most commonrelated AE in Study 1 was sensation of skin burning: 8 (1.8%) in IVM 1%subjects versus 6 (2.6%) for vehicle. For Study 2, the most commonrelated AEs for IVM 1% were pruritis and dry skin (3 subjects each(0.7%)) compared to 0 and 2 subjects (0.9%) for vehicle, respectively.In addition, laboratory tests did not demonstrate clinically significantabnormalities.

At baseline before treatment application, a large proportion of subjectspresented with local cutaneous symptoms consistent with rosacea,especially mild or moderate dry skin (for Studies 1 and 2, 63.0% and57.0% for IVM 1%, and 59.3% and 60.0% for vehicle, respectively) andmild or moderate itching (57.3% and 49.4% for IVM 1%, and 45.4% and49.1% for vehicle). At week 12 (last available data observed), themajority of subjects had none of the 2 cutaneous symptoms. A trend wasobserved in terms of absence of dryness in 83-86% of IVM 1% subjectsversus 72-76% for vehicle, as well as for absence of itching in 82-85%for IVM 1% versus 70-78% for vehicle.

Improvement after treatment was rated by subjects as “excellent” or“good” by 69% and 66.2% for IVM 1% compared to 38.6% and 34.4% forvehicle (p<0.001), respectively (FIGS. 6A and 6B). “Excellent”improvement was reported by 34.3% and 32.0% for IVM 1% versus 9.5% and7.3% for vehicle.

After 12 weeks of treatment, improved QoL scores were observed forsubjects in the IVM 1% compared to vehicle groups. For the DLQI, it isof note that no difference between treatment groups was observed atbaseline. At the end of each study, more subjects in the IVM 1% group(about 53%) than vehicle (about 35%) considered that their disease hadno effect on their overall QoL (p<0.001). For RosaQoL™, improvement inQoL from baseline was higher in both studies for IVM 1% (−0.64±0.7 and−0.60±0.6 versus −0.35±0.5 for both vehicle groups (p<0.001 and p=0.001for Studies 1 and 2, respectively). This result indicates that a higherproportion of subjects felt that their quality of life was notnegatively impacted by rosacea in the group treated with IVM, comparedto the control group treated with vehicle.

IGA was assessed during the second part of the studies (40 weeks). Thepercentages of subjects treated with IVM 1% achieving an IGA score of 0or 1 continued to increase up to week 52, the end of the second part ofthe studies. The success rate (IGA=0 or 1) at week 52 was 71.1% and 76%in studies 1 and 2 respectively. In both studies, the incidences werecomparable in the 2 groups of subjects treated by IVM 1% cream QD andazelaic acid 15% gel BID across the categories of related AEs,dermatologic AEs, serious AEs, related AEs leading to discontinuation,and AEs of special interests. There was no serious related AEs.

In the follow up third part of the studies, subjects treated with IVM 1%cream QD and azelaic acid 15% gel BID during the second part of thestudies were comparable in reporting AEs. No subjects reported relatedserious AEs, related AEs leading to discontinuation.

The most frequent (>0.5% in any arm) AEs were skin disorders, and wereless frequent with IVM 1% cream QD than azelaic acid 15% gel BID in bothstudies.

These two pivotal studies demonstrated the efficacy and safety oftopical ivermectin 1% cream in the treatment of inflammatory lesions ofrosacea with reproducibility. The effect was robust and highlysignificant (p,0.001) in all primary and secondary endpoints at week 12(ITT-LOCF). Onset of treatment effect was observed at week 4 in eachstudy based on both IGA and lesion counts. Onset of treatment effect wasobserved at week 2 in each study based on lesion counts. The ivermectin1% cream was well tolerated and safe in both studies. No notabledifference was observed between the ivermectin 1% cream QD andcorresponding vehicle and azelaic acid 15% gel BID. The most frequent(>0.5% in any arm) AEs were skin disorders, and were less frequent withIVM 1% cream QD than with the respective comparator. In addition, thecontinued daily application of the Ivermectin 1% Cream QD up to 1 yearis well tolerated, with no unexpected safety findings associated withchronic use.

In conclusion, ivermectin, such as 1% ivermectin cream, was effectiveand safe in treating papulopustular rosacea.

Example 4: Comparison of the Efficacy and Safety of Ivermectin 1% CreamVs. Metronidazole 0.75% Cream

This was an investigator-blinded, randomized, parallel group studycomparing the efficacy and safety of ivermectin (hereafter designatedIVM) 1% (w/w) cream vs. metronidazole 0.75% (w/w) cream with a 16-weekperiod A and a 36-week period B to study recurrence. Study visits duringPeriod A were as follows: a screening visit, and at baseline, weeks 3,6, 9, 12 and 16.

Eligible subjects were 18 years or older, with moderate or severepapulopustular rosacea as noted by an IGA of 3 (“several small or largepapules/pustules, moderate erythema”) or 4 (“numerous small and/or largepapules/pustules, severe erythema”), and presenting with 15-70 facialinflammatory lesions (papules and pustules).

Subjects were randomized in a 1:1 ratio to receive either IVM 1% cream(once daily, QD, at bedtime) or metronidazole 0.75% cream (twice daily,BID, as per labelling at morning and bedtime) for 16 weeks. Study drugswere applied in a thin film on the entire face (right and left cheeks,forehead, chin and nose), avoiding the upper and lower eyelids, lips,eyes and mouth. The subjects were instructed to maintain a consistentlifestyle throughout the study regarding rosacea triggers (i.e. avoidingenvironmental factors, certain foods, and excessive sun exposure).

Efficacy assessments at each visit were inflammatory lesion counts(papules and pustules) counted on five facial regions (forehead, chin,nose, right cheek, left cheek), and the Investigator's Global Assessment(IGA) of disease severity. Safety assessments included adverse events(AEs) throughout the study, local tolerance parameters(stinging/burning, dryness, itching) at each visit evaluated on a4-point scale (from 0 (none) to 3 (severe)), and laboratory parametersmeasured at baseline, weeks 9 and 16. Other assessments included thesubject's evaluation of rosacea improvement compared to their conditionat baseline, and subject's appreciation questionnaire at the end of thestudy (regarding satisfaction with the study drug). Lastly, a quality oflife questionnaire (Dermatology Life Quality Index (DLQI)) was completedat baseline and at the end of the study (week 16).

The ITT population included all subjects who were randomized and to whomthe study drug was administered. The safety population included allsubjects who received the study medication. The primary efficacyendpoint, percent change in inflammatory lesion counts from baseline toweek 16, was analyzed using the CMH test stratified on center, withridit transformation and row mean score difference statistic. Secondaryefficacy endpoints included success rate (percent of subjects with IGArated 0 (“clear”) or 1 (“almost clear”) (analyzed by CMH test stratifiedon center using general association statistic), IGA and absolute changein lesion counts (analyzed using ANCOVA, including treatments andanalysis center as factors, and baseline as covariate). LOCF was theprimary method for imputation of missing data, and multiple imputations(MI) method was used for sensitivity. Other variables were descriptivelyanalyzed.

A total of 1,034 subjects were screened and 962 randomized to receiveIVM 1% cream (n=478) or metronidazole 0.75% cream (n=484); 902 (93.8%)completed the study (FIG. 8). Treatment groups were comparable atbaseline in terms of demographics and baseline disease characteristics,with about 32 inflammatory lesions on average and the majority havingmoderate rosacea (83.3% with an IGA of 3) (Table 5). As expected, thequantity of product applied in the metronidazole group (BIDapplications) was nearly twice as much as the product applied in the IVM1% group (QD), with a mean of 1.31 g vs. 0.72 g, respectively.

TABLE 5 Demographic and baseline clinical characteristics (ITTpopulation) Ivermectin Metronidazole 1% 0.75% Total (n = 478) (n = 484)(n = 962) Age, years Mean ± SD 51.22 ± 13.40 51.87 ± 13.24 51.54 ± 13.32Min, Max 18, 85 18, 90 18, 90 Gender, n (%) Female 311 (65.1%) 316(65.3%) 627 (65.2%) Male 167 (34.9%) 168 (34.7%) 335 (34.8%) Race Asian 3 (0.6%) —  3 (0.3%) White 475 (99.4%)  484 (100.0%) 959 (99.7%) SkinPhototype I 18 (3.8%) 17 (3.5%) 35 (3.6%) II 245 (51.3%) 234 (48.3%) 479(49.8%) III 178 (37.2%) 213 (44.0%) 391 (40.6%) IV 36 (7.5%) 19 (3.9%)55 (5.7%) V  1 (0.2%)  1 (0.2%)  2 (0.2%) Inflammatory Mean ± SD 32.87 ±13.95 32.07 ± 12.75 32.46 ± 13.36 lesion Counts Investigator Global 3 =Moderate 398 (83.3%) 403 (83.3%) 801 (83.3%) Assessment 4 = Severe  80(16.7%)  81 (16.7%) 161 (16.7%)

Regarding the primary endpoint, at week 16 (ITT-LOCF), IVM 1% cream wassignificantly superior to metronidazole 0.75% cream in terms of percentreduction from baseline in inflammatory lesion counts (83.0% vs. 73.7%;p<0.001; FIG. 9). This difference was observed as early as week 3(ITT-LOCF) (as soon as week 6 with ITT-MI), and this continued throughweek 16 (all p-values ≤0.04). It should be noted that in this study,there was no study visit or assessment prior to Week 3, thus thedifferences in treatment could have been observed earlier than week 3 ifthe first study visit was conducted earlier. Similar results were foundfor the IGA success rate (subjects rated “clear” or “almost clear”):84.9% for IVM 1% cream vs. 75.4% for metronidazole 0.75% cream at week16 (ITT-LOCF) (p<0.001). As illustrated in FIG. 10, the difference inIGA was the highest at week 12 (14.9% superior for ivermectin).

About 13% more subjects were rated as “clear” in terms of IGA for IVM 1%than metronidazole 0.75% (34.9% vs. 21.7%, respectively). Furthermore,in a subgroup analysis of success rate according to IGA severity, about20% more subjects with severe rosacea at baseline in the IVM 1% groupachieved success (82.5% vs. 63.0%).

The incidence of adverse events (AEs) was similar between groups (32.4%vs. 33.1% of subjects in the IVM 1% and metronidazole 0.75% groups,respectively), as well as for related AEs (2.3% vs. 3.7%). Furthermore,a comparably low number of subjects experienced a related dermatologicAE (9 subjects (1.9%) in the IVM 1% group and 12 (2.5%) in themetronidazole 0.75% group). The most common related AE was skinirritation (3 subjects (0.6%) vs. 4 subjects (0.8%) for IVM 1% andmetronidazole 0.75%, respectively). Thirteen subjects reported seriousbut unrelated AEs. A total of 3 subjects (0.6%) in the IVM 1% groupexperienced related adverse events leading to discontinuation (due toskin irritation and hypersensitivity), compared to 10 (2.1%) subjects inthe metronidazole 0.75% group (due to skin irritation, allergicdermatitis, aggravation of rosacea, erythema, pruritis, and generaldisorders (hot feeling)).

In terms of local tolerance, the incidence of worsening from baselinewas higher in the metronidazole 0.75% group for stinging/burning (15.5%vs. 11.1%), dryness (12.8% vs. 10.0%), and itching (11.4% vs. 8.8%).Laboratory tests did not demonstrate clinically significantabnormalities.

At the end of period A of this study, the majority (85.5%) of subjectsin the IVM 1% group rated their global improvement as “excellent” or“good” compared to 74.8% in the metronidazole 0.75% group. Furthermore,more subjects receiving IVM 1% reported an “excellent” improvement oftheir rosacea (52.3% vs. 37.0%, respectively; FIG. 11). Regarding thesubject's appreciation questionnaire, more subjects in the IVM 1% groupwere satisfied with the study drug (76.0% vs. 61.3% in the metronidazole0.75% group). In addition, more subjects treated by IVM 1% tended toconsider the product easy to use and that the time needed forapplication was satisfactory, whereas more subjects found metronidazole0.75% to be irritating (data not shown).

At baseline, the mean DLQI scores were similar between groups (6.95 forIVM 1% and 6.05 for metronidazole 0.75%, respectively). Patients treatedwith IVM 1% showed a higher numerical decrease in their DLQI score thanpatients treated with metronidazole 0.75% (−5.18 vs. −3.92; p<0.01),indicating a higher improvement in quality of life. At the end of thestudy, 71% of patients treated with IVM 1% reported no effect at all ontheir quality of life (vs. 64% for metronidazole 0.75%), which meansthat a higher proportion of subjects felt that their quality of life wasnot negatively impacted by rosacea in the group treated with IVM,compared to the group treated with metronidazole. The study drugsdiverged in favor of IVM 1% in the symptoms and feelings sub-scale(level of itching, soreness, pain or stinging: “not at all” for 78.7%vs. 63.0% in the metronidazole 0.75% group; level of embarrassment orself-consciousness: “not at all” for 70.3% vs. 60.1%, respectively).

Topical metronidazole 0.75% (w/w) has been one of the most frequentlyused therapies in the treatment of papulopustular rosacea. In thisstudy, IVM 1% cream was significantly superior to metronidazole 0.75%cream in terms of percent reduction from baseline in inflammatory lesioncounts, with an onset of efficacy (first difference vs. metronidazole0.75%) as early as 3 weeks (or even earlier) that continued through 16weeks. The findings show that ivermectin is more efficacious thanmetronidazole, with a tendency even in patients with higher lesioncounts.

An overall good safety profile was observed for IVM, and it waswell-tolerated in comparison with metronidazole. It is not surprisingthat for both products, patients experienced a similarly low number ofrelated adverse events, particularly since the tolerability ofmetronidazole is known to be satisfactory. Metronidazole's higherincidence of worsening from baseline concerning stinging/burning,dryness, and itching may be attributed to the usual signs and symptomsof rosacea. Nevertheless, this affected the level of quality of life asmeasured by the DLQI, as more patients in the metronidazole groupreported itching, soreness, pain or stinging.

Patient-reported outcomes for IVM 1% cream were consistent with itssuperior efficacy results. More patients using IVM indicated that theproduct was easy to use and that the time needed for application wassatisfactory, implying that the daily application is more convenientthan metronidazole's twice-daily regimen. Related to quality of lifemeasures, fewer patients using IVM considered themselves to beembarrassed or self-conscious. Thus, ivermectin appears to be adapted tothe complex etiology of rosacea, and in the study IVM 1% creamdemonstrated superiority to metronidazole 0.75% cream in terms ofinflammatory lesion reduction. As noted in the afore-mentioned Cochranereview, few robust studies have compared topical metronidazole withanother rosacea treatment and in three identified studies, topicalmetronidazole was either non-significantly different or less effectivethan azelaic acid.⁸ While metronidazole has been used in the past as areasonable treatment for the papulo-pustular lesions of rosacea, itsefficacy is surpassed by that of ivermectin along with the advantage ofonce-daily dosing.

The relapse among subjects successfully treated at the end of the PeriodA was studied during the treatment free Period B (36 weeks). At the endof Period A, only subjects with an IGA of “0” or “1” (clear or almostclear) were eligible for entering Period B. Then, their study treatmentwas discontinued and the subjects were followed for up to 8 months (36weeks). In case of reoccurrence of an IGA of at least “2” (mild) at anytime during Period B, the subjects were retreated with the sametreatment received during the Period A. The re-treatment was stopped assoon as the IGA was back to “0” or “1” (clear or almost clear). Themaximum duration of re-treatment was 16 consecutive weeks to mimic thePeriod A treatment duration. In order to characterize the relapses, thefollowing parameters were assessed: (1) time of first relapse (timeelapsed between Week 16 and first reoccurrence of IGA at “2”, “3” or “4”inducing a retreatment course), (2) relapse rate (percentage of subjectswith reoccurrence of IGA at “2”, “3” or “4” after a period free of studytreatment) and (3) number of days free of treatment.

At the start of Period B, treatment groups were comparable with respectto the demographic. Of the total 757 subjects included in Period B (399in Ivermectin 100 and 358 in Metronidazole 0.75% groups, respectively),504 (66.6%) were female, 754 (99.6%) were Caucasian and the mean age was51.9 years. In terms of disease characteristics, the means inflammatorylesion counts were similar in both groups (median 2.0). But, theproportion of subjects with an IGA of 0 was higher in Ivermectin groupthan in Metronidazole group (41.6% versus 29.1%) due to the higherefficacy of Ivermectin treatment from Period A.

TABLE 6 End of Period A disease characteristics of subjects enteringPeriod B Ivermectin Metronidazole TOTAL Inflammatory N 399 358 757lesion counts Mean 2.58 2.96 2.76 SD 3.20 3.42 3.31 Median 2.00 2.002.00 Min~Max  0~19  0~24  0~24 P25~P75 0~4 0~4 0~4 Investigator N 399358 757 Global Assessment 0 = Clear 166 (41.6%) 104 (29.1%) 270 (35.7%)1 = Almost Clear 233 (58.4%) 254 (70.9%) 487 (64.3%) Nodules N 399 358757 0 397 (99.5%) 357 (99.7%) 754 (99.6%) 1  2 (0.5%)  1 (0.3%)  3(0.4%) Papules N 399 358 757 Mean 2.27 2.56 2.40 SD 2.77 2.83 2.80Median 2.00 2.00 2.00 Min~Max  0~16  0~17  0~17 P25~P75 0~4 0~4 0~4Pustules N 399 358 757 Mean 0.32 0.40 0.36 SD 0.91 1.20 1.06 Median 0.000.00 0.00 Min~Max 0~9  0~12  0~12 P25~P75 0~0 0~0 0~0

The time to first relapse, defined as time elapsed between Week 16 andfirst reoccurrence of IGA at “2”, “3” or “4” was analyzed following 2definitions: (1) the first one was based on IGA only; and (2) the secondone took also into account any major deviations by imputing relapse theday of first major deviation. For each definition, a sensitivityanalysis was performed by imputing relapse 4 weeks after discontinuationfor all subjects who discontinued early from Period B without relapse.Relapse rates followed the same convention analyses as the time torelapse.

The median times to first relapse were 115 days for ivermectin 1% QD and85 days for Metronidazole 0.75% BID (p=0.0365), the relapse rates were62.7% and 68.4% respectively (Table 7). See also FIG. 12. Whenconducting the sensitivity analysis by imputing relapse 4 weeks later tosubjects who discontinued early without relapse, the medians were 114days and 85 days (p=0.0594) and the relapse rates were 66.2% and 70.4%,respectively. Similar results were obtained when taking also intoaccount the day of first major deviation.

TABLE 7 IVM 1% Metronidazole p-value (1) N 399 358 0.0365 Median and 95%115.0┌113; 165┐ 85.0┌85; 113┐ — Confidence Interval Mean ± Standard147.0 ± 4.66 133.6 ± 5.13 — Error Relapse is based on IGA only (1)Logrank test

Number of days free of treatment was defined for each subject enrolledin period B as the time interval between a visit where IGA is assessedas 0 or 1 and the next visit. The number of treatment-free days is thesummation over all visits of period B meeting this criterion. Anadditional analysis was also performed by subtracting from the days freeof treatment any time interval between visits when the subject whilebeing IGA 0 or 1 had a major protocol deviation.

Based on IGA score showed a mean days free of treatment of 183 days forivermectin 1% QD versus 170 days for metronidazole (p=0.026). Whentaking into account the protocol deviations the mean days free oftreatment remained nearly the same 181 days versus 168 days (p=0.021) infavor of ivermectin 1% QD.

Ivermectin 1% cream QD treatment resulted in a statistically significantextended remission (i.e. delayed time to first relapse, and increase inthe number of treatment free days) of rosacea when compared toMetronidazole 0.75% BID in subjects who were successfully treated (IGA 0(clear) or 1 (almost clear)) for 16 weeks. There was also a numericaltrend in favor of Ivermectin 1% cream QD for the relapse rates (62.7%and 68.4% in the Ivermectin 1% group and Metronidazole 0.75% group,respectively). It should be noted that the differences observed in favorof Ivermectin 1% in Period B are presumably the consequence of thehigher efficacy of Ivermectin compared to Metronidazole observed at theend of Period A, with a higher proportion of subjects with an IGA=0 inthe Ivermectin group (41.6% and 29.1% in Ivermectin and Metronidazole,respectively).

The overall pharmacoeconomic benefit of Ivermectin 1% cream QD versusMetronidazole 0.75% cream BID over the one year duration of the study(Period A & B), is considerable when viewed as the sum of the followingelements: benefit of Ivermectin over Metronidazole observed at the endof Period A (84.9% of success in Ivermectin group Vs. 75.4% inMetronidazole group), time to first relapse (115 Vs. 85 days), relapserate (62.7% Vs. 68.4%) and number of days free of treatment (183.4 Vs.170.4).

Example 5: Plasma Pharmacokinetic Study

A multi-center, open-label, single treatment study was conducted toassess the pharmacokinetic (PK) profile of ivermectin 1% (w/w) cream insubjects with severe PPR. A maximized dose of about 2 mg/cm² (1 g ofivermectin 1% (w/w) cream, equivalent to 10 mg ivermectin perapplication) was applied to the face once daily for 4 weeks. Thetreatment was followed by a 28-Day follow-up period.

A total of seventeen subjects received at least one dose of treatment.All subjects provided PK parameters at some time points, but fifteen (9females and 6 males) provided full PK profiles at Days 0, 14 and 28.These fifteen subjects had an inflammatory lesion count of 27 to 88lesions and severe papulo-pustular rosacea (IGA score 4) at baseline(pretreatment).

Blood samples for determination of ivermectin levels in plasma weretaken from all subjects before application on Days 0, 7, 14, 21 and 28(pre-dose samples corresponding to C_(min)). Additional blood sampleswere taken on Days 0, 14 and 28 at 1, 3, 6, 9 and 12 hours afterapplication. At the end of the 28-Day treatment, blood samples weretaken on Days 29, 30, 32, 35, 38, 42, 49 and 56 during the follow-upperiod. The plasma was isolated and frozen (−20° C.) pending analysis.

The pharmacokinetic analysis was performed. From the individual plasmaconcentrations, the pharmacokinetic parameters were determined bynon-compartmental method Kinetica™ sofware, version 4.3, InnaPhaseCorporation, Philadelphia, USA).

During the treatment period, the following parameters were measured:

-   -   (1) C_(min): The pre dose plasma concentration of the drug at        Days 0 (24 hours after DO, pre-dose of Day 1), 7, 14, 21 and 28;    -   (2) C_(max): The observed peak drug concentration at Days 0, 14        and 28;    -   (3) T_(max): The time at which C_(max) occurs at Days 0, 14 and        28;    -   (4) AUC_(0-24H): Area under the concentration-time curve from        pre-application (T0) through 24 hours post dosing corresponding        to the dosing interval. AUC_(0-24H) was calculated by the mixed        linear-logarithmic trapezoidal method at Day 0, 14 and 28. BLQ        was imputed as zero in the individual PK profile.

During the follow up period, the following parameters were measured:

-   -   (1) AUC0-t: Area under the concentration-time curve calculated        by the mixed linear-logarithmic trapezoidal method from T0 up to        the sampling time corresponding to the last quantifiable        concentration (Clast);    -   (2) Kel: The elimination rate constant value (kel) was obtained        by linear regression of log-linear terminal phase of        concentration-time profile using at least 3 data points,        excluding Cmax, otherwise kel was not determined. The        acceptability criteria for determination of kel was a        coefficient of regression more or equal to 0.98. When kel was        not determined, AUC0-inf and t1/2 were not reported;    -   (3) t½: The terminal half-life value (t½) was calculated using        the equation ln 2/kel;    -   (4) AUC0-inf: Area under the plasma concentration-time curve        calculated by the mixed linear-logarithmic trapezoidal method        from T0 and extrapolated to time infinity as:        AUC0-inf=AUC0-t+Clast/kel.

When the extrapolation represented more than 20%, AUC_(0-inf) andt_(1/2) were reported. Mean values, standard deviation (SD), lowestindividual value (Min), maximal individual value (Max) and coefficientof variation (CV) were calculated and reported on each variables(Arithmetic mean for AUC, C_(max), T_(max) and harmonic mean fort_(1/2)). Conversely to the protocol, the standard error of mean (SEM)were not calculated and not reported. In addition a statistical analysiswas performed on ivermectin specific parameters (including theaccumulation ratios).

A total of seventeen subjects received at least one dose of treatment.All subjects provided PK parameters at some time points, but fifteen (9females and 6 males) provided full PK profiles at Days 0, 14 and 28. ThePK parameters from all the subjects are presented in this report (17subjects at Days 0/1 and 15 subjects in the subsequent days).

No unacceptable deviations were observed between the actual andtheoretical sampling times (according to predefined acceptable range).Consequently, the theoretical sampling times were used for PK analysis.Individual ivermectin plasma concentrations determined during thetreatment period are summarized in Table 8.

TABLE 8 pharmacokinetics parameters at various treatment period: Mean ±SD (N = 15) Parameters Day 0^((a)) Day 7 ^((b)) Day 14 Day 21 Day 28Pre-dose/C_(min)  0.37 ± 0.21^((a)) 1.17 ± 0.88  1.26 ± 0.53^((c)) 1.36± 0.66^((c)) 1.36 ± 0.63 (ng/mL): [0.17-0.86] [0.56-3.26] [0.58-2.34][0.66-3.25] [0.53-3.00] mean ± SD Min-Max C_(max) (ng/mL): 0.69 ± 0.492.10 ± 1.04 1.74 ± 0.77 mean ± SD [0.19-1.76] [0.69-4.02] [0.58-3.36]Min-Max T_(max) (h): 9 ± 6 10 ± 8  11 ± 4  mean ± SD  [1-24]  [0-24] [3-24] Min-Max AUC_(0-24 H) 9.29 ± 5.40 36.14 ± 15.56 35.43 ± 14.42 (ng· h/mL):  [3.16-21.28] [13.69-75.16] [12.89-70.08] mean ± SD Min-Max^((a))N = 17, ^((b)) N = 13, ^((c))N = 14

The arithmetic mean ivermectin plasma profiles over the 28-Day treatmentapplication are exhibited in FIG. 13. The mean±SD and the range(Min-Max) values of C_(min), C_(max), and AUC_(0-24H) on all samplingdays are given up in Table 8.

After one single topical application of ivermectin cream 1%,quantifiable ivermectin levels were found in the plasma of the 17subjects assigned to treatment. A high inter-individual variability wasobserved as evidenced by the coefficient of variation (CV) ranging from57 to 71%. After a single topical application (Day 0) a flat PK profilewas observed over the dosing interval, plasma concentrations ofivermectin peaked within 9 hours post dose (0.69 ng/mL range: 0.19-1.76ng/mL) and then slowly decreased thereafter up to 0.37 ng/mL, 24 hourspost dose.

After a 28-day of once daily topical application of ivermectin cream 1%,the systemic exposures are higher than the ones calculated after onesingle application. A lower inter-individual variability was observedafter repeated dosing, with CV ranging from 39% to 46%.

The systemic exposures over the dosing interval calculated at Day 14(AUC_(0-24H): 36.14±15.56 ng·h/mL) and at Day 28 (AUC_(0-24H):35.43±14.42 ng·h/mL) were similar, indicating that the steady state wasreached as early as 14 days after the initial administration. The sametendency was observed with the pre-dose plasma concentrations. The mean(±SD) pre-dose concentrations of ivermectin were 1.26±0.53 ng/mL,1.36±0.66 ng/mL and 1.36±0.63 ng/mL at Day 14, Day 21 and Day 28,respectively.

After the very latest topical application of ivermectin (Day 28), theapparent terminal half-life determined from 14 enrolled subjects was 145hours (range 92-238 hours), the last quantifiable concentration beingobserved approximately 24 days after application. In addition the totalsystemic exposure at Day 28 (AUC_(0-inf)) was 312±173 ng·h/mL. Thisprolonged apparent half-life indicates that ivermectin was slowlycleared from plasma after the ivermectin treatment was stopped.

After a 28-Day once daily topical application of ivermectin cream 1%,the systemic exposure of ivermectin over the dosing interval calculatedat Day 14 (AUC_(0-24H): 36.14±15.56 ng·h/mL, range 13.69-75.16 ng·h/mL)and at Day 28 (AUC_(0-24H): 35.43±14.42 ng·h/mL, range: 12.89-70.08ng·h/mL) were similar, indicating that the steady state was reached byDay 14. At steady state (after 2 weeks of treatment), the highest mean(standard deviation) plasma concentrations of ivermectin peaked within10±8 hours post-dose dose (Cmax: 2.10±1.04 ng/mL range: 0.69-4.02 ng/mL)and the highest mean (standard deviation) AUC 0-24 hr was 36.14±15.56ng·hr/mL (range: 13.69-75.16 ng·hr/mL). These levels obtained understeady-state conditions are lower than those observed following oraladministration of ivermectin (relative bioavailability of 16%).Additional systemic exposure assessment in a longer treatment duration(Phase 3 study) evidenced that there was no plasma accumulation ofivermectin over a 52-week treatment period, indicating that ivermectinis safe and can be administered for a long period of time.

At the end of the 28-Day application period, ivermectin was slowlycleared from the plasma with an apparent plasma terminal half-life of145 hours, the last quantifiable concentration being observedapproximately 24 days after application. This terminal half-life is moreprolonged than the one published for an oral administration ofivermectin. The t_(1/2) for ivermectin orally administered is typicallyaround 18 hours, ranging from about 12 to 20 hours (Fink et al, Guzzo etal). This prolonged terminal half-life after topical administrationsuggest that the rate limiting step in plasma ivermectin concentrationdecrease is the ivermectin disappearance from the administration siterather than the elimination rate. The term of flip-flop is used todescribe this phenomenon (Toutain et al, 2004, supra).

In conclusion, the once daily topical treatment with 1% ivermectin issafe and can be conducted for as long as it is needed without causingany safety concerns.

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It will be appreciated by those skilled in the art that changes could bemade to the embodiments described above without departing from the broadinventive concept thereof. It is understood, therefore, that thisinvention is not limited to the particular embodiments disclosed, but itis intended to cover modifications within the spirit and scope of thepresent invention as defined by the appended claims.

I/We claim:
 1. A method of treating inflammatory lesions of rosacea in asubject in need thereof, comprising topically administering, once daily,to a skin area affected by the inflammatory lesions of rosacea anemulsion comprising 1% by weight ivermectin and a pharmaceuticallyacceptable carrier, without co-administration of another activepharmaceutical ingredient.
 2. The method of claim 1, wherein thetreatment results in more reduction in inflammatory lesion count in thesubject in comparison to that achieved by topically administering to thesubject, twice daily, a second pharmaceutical composition comprising0.75% by weight metronidazole.
 3. The method of claim 1, wherein thetreatment results in longer relapse-free time of the inflammatorylesions of rosacea in the subject in comparison to that achieved bytwice daily topically administering to the subject a secondpharmaceutical composition comprising 0.75% by weight metronidazole. 4.The method of claim 1, wherein the treatment has a median time to firstrelapse of 110 days or longer.
 5. The method of claim 1, wherein thesubject has moderate to severe papulopustular rosacea before thetreatment.
 6. The method of claim 5, wherein the subject has 15 or moreof the inflammatory lesions before the treatment.
 7. The method of claim1, wherein a steady state of plasma concentration of ivermectin isreached in the subject as early as 2 weeks after the initialadministration of the emulsion to the subject, wherein the steady statehas a C_(max) of ivermectin of 0.5-10 ng/mL, and an AUC_(0-24hr) of10-100 ng·hr/mL in the subject.
 8. The method of claim 1, wherein animprovement from the baseline in an investigator's global assessment(IGA) of rosacea severity, and/or a significant reduction ininflammatory lesion count, is observed 8 weeks after the initialadministration of the emulsion.
 9. The method of claim 1, wherein animprovement from the baseline in an investigator's global assessment(IGA) of rosacea severity, and/or a significant reduction ininflammatory lesion count, is observed 12 weeks after the initialadministration of the emulsion.
 10. The method of claim 1, wherein theemulsion is a cream that further comprises one or more ingredientsselected from the group consisting of an oily phase comprisingdimethicone, cyclomethicone, isopropyl palmitate and/or isopropylmyristate, the oily phase further comprising fatty substances selectedfrom the group consisting of cetyl alcohol, cetostearyl alcohol, stearylalcohol, palmitostearic acid, stearic acid and self-emulsifiable wax; atleast one surfactant-emulsifier selected from the group consisting ofglyceryl/PEG100 stearate, sorbitan monostearate, sorbitan palmitate,Steareth-20, Steareth-2, Steareth-21 and Ceteareth-20; a mixture ofsolvents and/or propenetrating agents selected from the group consistingof propylene glycol, oleyl alcohol, phenoxyethanol and glyceryltriacetate; one or more gelling agents selected from the groupconsisting of carbomers, cellulose gelling agents, xanthan gums,aluminum magnesium silicates but excluding aluminum magnesiumsilicate/titanium dioxide/silica, guar gums, polyacrylamides andmodified starches; and water.
 11. The method of claim 1, wherein thetopical administration of the emulsion to the subject results in a meanterminal half-life of ivermectin of about 145 hours in the subject. 12.A method of treating inflammatory lesions of rosacea in a subject inneed thereof, comprising topically administering, once daily, to a skinarea affected by the inflammatory lesions a cream comprising 1% byweight ivermectin and a pharmaceutically acceptable carrier, withoutco-administration of another active pharmaceutical ingredient, whereinthe pharmaceutically acceptable carrier comprises an oily phase, asurfactant-emulsifier, a mixture of solvents and/or propenetratingagents, a gelling agent, and water, and wherein an improvement from thebaseline in an investigator's global assessment (IGA) of rosaceaseverity, and/or a significant reduction in inflammatory lesion count,is observed 12 weeks after the initial administration of the emulsion.13. The method of claim 12, wherein an improvement from the baseline inan investigator's global assessment (IGA) of rosacea severity, and/or asignificant reduction in inflammatory lesion count, is observed 8 weeksafter the initial administration of the emulsion.
 14. The method ofclaim 12, wherein the subject has moderate to severe papulopustularrosacea before the treatment.
 15. The method of claim 14, wherein thesubject has 15 or more of the inflammatory lesions before the treatment.16. The method of claim 12, wherein the oily phase comprisesdimethicone, cyclomethicone, isopropyl palmitate and/or isopropylmyristate, the oily phase further comprises fatty substances selectedfrom the group consisting of cetyl alcohol, cetostearyl alcohol, stearylalcohol, palmitostearic acid, stearic acid and self-emulsifiable wax;the surfactant-emulsifier is selected from the group consisting ofglyceryl/PEG100 stearate, sorbitan monostearate, sorbitan palmitate,Steareth-20, Steareth-2, Steareth-21 and Ceteareth-20; the mixture ofsolvents and/or propenetrating agents is selected from the groupconsisting of propylene glycol, oleyl alcohol, phenoxyethanol andglyceryl triacetate; the gelling agent is selected from the groupconsisting of carbomers, cellulose gelling agents, xanthan gums,aluminum magnesium silicates but excluding aluminum magnesiumsilicate/titanium dioxide/silica, guar gums, polyacrylamides andmodified starches.
 17. The method of claim 12, wherein the creamcomprises carbomer copolymer type B; cetyl alcohol; citric acidmonohydrate; dimethicone 20 Cst; edetate disodium; glycerin; isopropylpalmitate; methyl paraben; oleyl alcohol; phenoxyethanol; polyoxyl 20cetostearyl ether; propylene glycol; propyl paraben; purified water;sodium hydroxide; sorbitan monostearate and stearyl alcohol.
 18. Themethod of claim 17, wherein an improvement from the baseline in aninvestigator's global assessment (IGA) of rosacea severity, and/or asignificant reduction in inflammatory lesion count, is observed 8 weeksafter the initial administration of the emulsion.
 19. The method ofclaim 17, wherein the subject has moderate to severe papulopustularrosacea before the treatment.
 20. The method of claim 17, wherein thesubject has 15 or more of the inflammatory lesions before the treatment.